The projected expansion in U.S. corn-based ethanol production over the next several years has created concern that large surpluses of distillers grains may result. Most of the distillers grains currently being produced are consumed by the domestic livestock and poultry industries, especially the beef industry. A recent study by the Center for Agricultural and Rural Development projects that the U.S. ethanol industry could produce between 40 million and 88 million metric tons of distillers grains (dry matter basis) per year by 2011. The proportion of these distillers grains that would need to be consumed by the beef industry to prevent surpluses poses questions about how much distillers grains can be included in beef rations, the effects of feeding distillers grains on beef quality, and how current consumption patterns are likely to change as production of distillers grains increases. As more data from feeding trials have become available, a better understanding of the benefits and effects of feeding distillers grains is emerging. In this paper, we use results from a recent USDA producer survey about co-product use in beef production to project how current patterns of use are likely to change as the volume and availability of distillers dried grains increases. We then review recent results from feeding trials using distillers grains in beef rations, including nutritional value and effects on live animal performance and beef quality. Finally, we discuss some of the new technologies being used to improve distillers grains as a ration ingredient and present some general conclusions.